220 THE BACTERIOPHAGE 



The animals which resisted, therefore, showed in their intestine 

 a bacteriophage virulent for the pathogenic bacterium. 



The epizootic does not always remain localized in a village. 

 At times it spreads rapidly from village to village and within a 

 few days will extend over a very considerable territory. It is 

 rarely possible to determine the primary focus, so great is the 

 speed with which it spreads. The mortality then becomes con- 

 siderable, the losses often amount to tens of thousands of animals, 

 as has been observed many times in China, in British India, and 

 in the Dutch East Indies. Sometimes even, as actually happened 

 in Java, the buffalo, as a race, is practically eliminated. 



In the first two weeks of June 1920 the epizootic became general 

 in the Province of Bac Lieu and in certain parts of the adjacent 

 provinces (western Cochin-China). It was possible to examine 

 the blood of eleven animals which died in widely scattered parts 

 of the area invaded, and in all the bacterium of barbone was found 

 in considerable quantity. 9 The epizootic died out during the first 

 fortnight of July. It had persisted for a month, killing a third 

 of the animals in the district. 



The region of Thoi Binh was particularly affected, the loss 

 amounting to more than fifty per cent of the buffaloes in the 

 locality. From July 8 to 13, at the time when the epizootic was 

 disappearing (the last animal to be affected died on July 12), 

 twenty specimens of feces were collected. These were taken from 

 buffaloes which had resisted the infection and which at no time 

 showed any evidence of the typical symptoms of the disease. 

 All of the animals examined lived on the farms of the village 

 of Thoi Binh or in the neighboring hamlets within a radius of 

 fifteen kilometers. 



Tests for the virulence of the intestinal bacteriophage against 

 the bacterium of barbone gave the following results: 



9 Bacteriological diagnosis is easy, even if the only available material 

 is some blood or a fragment of an organ taken without any special pre- 

 cautions in the field, as is usual in such countries. Even if the specimen 

 is some days old it is only necessary to smear it over the shaved skin of a 

 rabbit. If the bacterium of barbone is present the animal will die within 

 24 hours, and the organism will be found in pure culture in the blood, from 

 which it may be readily isolated. This is also the best method for detecting 

 the bacterium in soil or in fecal material. 



